Remove extraneous error message

COUCHDB-2787
diff --git a/src/mango_error.erl b/src/mango_error.erl
index 4704261..9b7ae82 100644
--- a/src/mango_error.erl
+++ b/src/mango_error.erl
@@ -69,7 +69,7 @@
     {
         400,
         <<"text_search_error">>,
-        fmt("Error performing text search: ~p", [Error])
+        fmt("~p", [Error])
     };
 
 info(mango_fields, {invalid_fields_json, BadFields}) ->